Why buy veggies if you can grow them yourself for less, right? That appears to be why the number of U.S. homes buying seeds spiked starting in 2007, and the National Gardening Association projected that 43 million U.S. households grew their own fruits, vegetables, berries and herbs in 2009, an increase of 19% from the year before. Some seed stores have even seen a 75% spike in sales.